i wrote a book - active the book is written by me -- passive

Let's imagine that you went on a sea voyage and discovered a new continent. :) Here's a sentence that describes what happened: "Helga discovered a new continent." What is the action? - discovered Who is the doer of the action? - Helga Who//what is the receiver of the action? - a new continent Newspapers would immediately publish a story about your amazing discovery. The title would be something like, "A New Continent is Discovered" (passive voice). The title wouldn't be, "Helga Discovered a New Continent" (active voice). Why? Because the news-worthy event is that a new continent was discovered. Who discovered it is less important. The usual order in which sentences are formed, DOER + ACTION + RECEIVER, is reversed in the passive voice: RECEIVER + ACTION + (DOER). The passive voice is used to emphasize the action and the receiver of the action (new continent was discovered) rather than the doer of the action (Helga). Usually, the doer is not mentioned in the passive voice. Here's another example. Let's say you are a scientist. You are researching the side effects of a new drug by testing it on mice. In a report about your findings, you would write something like "the mice were given 10 mg of the drug every day." This sentence is an example of the passive voice. You would not use the active voice--"I gave the mice 10 mg of the drug every day"--because (1) it's not important to know who gave them the drug, and (2) it's obvious from the context that the scientist performing the study gave them the drug. You would also write, "the mice were observed for 30 days," instead of "I observed the mice for 3 days."

Active costructions are used more often in English than passive constructions. Generally, you need the passive voice when it is not known or not necessary to mention who performs the action: cotton is grown in Egypt; his book hasn't been published yet; his house was built a year ago; the film will be released in a month. Don't use passive constructions unnecessarily. In many cases it is better to use active constructions if you know who performs the action. Normal: I've already bought a new computer. Strange: A new computer has been bought by me already.

It would be better to use passive voice if you want to achieve an academic writing .